1. Field of the Invention:
The present invention relates to a replenishing device for replenishing replenishing tanks with replenishing processing chemicals upon starting development processing or the like and to a replenishing device capable of detecting failures of replenishing means which replenish replenishing processing chemicals into processing baths and a method for detecting failures in the replenishing device, both of which can be applied to, for example, a printer-processor which is a combination of a photographic printer and a processor.
2. Description of the Related Art:
A printer-processor is a so-called "mini-laboratory" and is used in a developing, printing and enlargement (DPE) shop or the like. In the printer-processor, a printer unit, which prints/exposes images recorded on a negative film onto photographic paper, and a processor unit, which effects development processing of the printed and exposed photographic paper, are combined into a single unit. By simply setting an elongated photographic paper at the printer-processor, the photographic paper can be automatically conveyed to the printer unit and the processor unit and processed thereat.
In the printer unit of the printer-processor, the images recorded on the negative film are enlarged to selected predetermined sizes and are printed on photographic paper. The photographic paper on which the images of the negative film have been printed is successively conveyed to the processor unit where the negative film is subjected to development processing so that the images are finished as photographic prints.
Further, a plurality of processing baths for respectively performing processes such as development, bleaching/fixing and washing are provided in the processor unit. Replenishing tanks for respectively storing replenishing processing solutions therein are coupled to their corresponding processing baths through replenishing pumps. By respectively feeding the replenishing processing solutions into the processing baths from the replenishing tanks via the replenishing pumps, the respective processing baths are respectively replenished with the replenishing processing solutions to recover depletion of processing solutions within the processing baths and maintain the processing solutions in a stable state.
In general, a liquid level detector such as a float switch or the like is provided near the bottom of a replenishing tank. When a level of replenishing processing solution is detected by the level detector, a system judges that there is no replenishing processing solution and immediately produces an alarm to tell an operator to put replenishing processing solution into the replenishing tank.
With recent advances, the remaining quantity of replenishing processing solution in a replenishing tank is now recognized by attaching a rotary encoder or the like to a rotatable shaft of a replenishing pump and detecting the quantity of replenishing processing solution fed into a processing bath from the replenishing tank. If it is judged that there is no replenishing processing solution, an alarm is sounded to immediately tell the operator to put the replenishing processing solution into the replenishing tank. Therefore, development processing executed by a printer-processor must be discontinued each time the alarm sounds, thereby causing a reduction in work efficiency.
On the other hand, since the number-of-revolutions detector such as the rotary encoder or the like is expensive and is contrary to a demand for a reduction in the manufacturing cost of the printer-processor, non-detection of the number of revolutions of a replenishing pump was investigated. It has therefore been considered that the remaining quantity of replenishing processing solution in a replenishing tank be recognized based on an estimated value indicative of the quantity of replenishing processing solution fed into a processing bath without directly detecting the number of revolutions of the replenishing pump.
However, if the supply of the replenishing processing solution to the processing bath from the replenishing tank is stopped due to failure in the replenishing pump, then the failure cannot be detected. It is therefore necessary to provide a means for detecting such a failure at an early stage.